Modular trailing arm suspension

ABSTRACT

A modular suspension ( 10 ) adapted to mount on a vehicle frame having a pair of spaced C-shaped frame rails ( 12 ). The modular suspension comprises a pair of trailing arm assemblies ( 14 ) connected by a cross beam ( 50 ) and a trailing arm connection. Each of the trailing arm assemblies comprises a frame bracket ( 18 ) adapted to be mounted to one of the frame rails and a trailing arm ( 16 ) having one portion pivotally mounted to the frame bracket for pivotal movement about a pivot axis. The trailing arm connection ( 42, 52 ) extends between and is coupled to a portion of the trailing arms rearward of the pivot axis. The cross beam extends between and connects to the frame brackets such that a rail opening ( 56 ) having a shape for slidably receiving at least a portion of one of the frame rails is formed between each of the frame brackets and the cross beam. The modular suspension can be mounted to the frame rails by aligning each of the frame rails with each of the rail openings and moving the modular suspension longitudinally relative to the frame rails.

RELATED APPLICATIONS

This application claims the benefit of International Patent ApplicationNo. PCT/US00/20442, filed Jul. 27, 2000, which claims the benefit ofU.S. Provisional Patent Application No. 60/146,603 filed Jul. 30, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a trailing arm suspension comprising a pair oftrailing arm assemblies mounted to the frame rails of a vehicle andcarrying an axle having ground engaging wheels. In one of its aspects,the invention relates to a trailing arm suspension module where thetrailing arm assemblies are interconnected and prepositioned forinstallation so that the module can be directly installed to the vehicleas an integral unit.

2. Description of the Related Art

Heavy-duty vehicles such as semi-tractor/trailers typically havemultiple trailing arm suspensions comprising a pair of trailing armassemblies mounted to the vehicle or trailer frame and carrying an axlewith ground engaging wheels. The axle can be either a drive axle or anon-drive axle. The trailing arm assemblies typically comprise atrailing arm having first and second ends. The first end is pivotallyconnected to a hanger bracket that is directly connected to the vehicleframe. The second end mounts one portion of an air spring having anotherportion mounted to the vehicle frame. The trailing arm is free to rotateabout the pivotal connection with the hanger bracket and the air springdampens the rotational movement of the trailing arm. The axle spans theopposing trailing arms and is secured to the trailing arms by suitablebrackets. The trailing arm suspension can include other components suchas shock absorbers and torsion rods, for example.

In all current trailing arm suspensions, the trailing arm assemblies andpartial subassemblies of the other suspension components are built up onthe vehicle. In other words, the trailing arm suspension is installed ormounted to the vehicle frame by sequentially mounting andinterconnecting each of the components or partial subassemblies to eachother on the vehicle frame as required. The build up approach toassembling and installing the trailing arm suspension requires arelatively long time and it is highly desirable to reduce the assemblytime of the trailing arm suspension to reduce assembly costs.

SUMMARY OF THE INVENTION

The invention relates to a modular suspension adapted to mount on avehicle frame having a pair of spaced C-shaped frame rails. The modularsuspension comprises a pair of trailing arm assemblies connected by across beam and a trailing arm connection. Each of the trailing armassemblies comprises a frame bracket adapted to be mounted to one of theframe rails and a trailing arm having one portion pivotally mounted tothe frame bracket for pivotal movement about a pivot axis. The trailingarm connection extends between and is coupled to a portion of thetrailing arms rearward of the pivot axis. The cross beam extends betweenand connects to the frame brackets such that a rail opening having ashape for slidably receiving at least a portion of one of the framerails is formed between each of the frame brackets and the cross beam.The modular suspension can be mounted to the frame rails by aligningeach of the frame rails with each of the rail openings and moving themodular suspension longitudinally relative to the frame rails.

The modular suspension further comprises a connector mounting each ofthe frame brackets to the cross beam. The connector can comprise aspacer mounted between a portion of the frame bracket and the crossbeamand a removable fastener secures the spacer to the frame bracket andcross beam.

The trailing arm connection can comprise an axle mounted to the trailingarms for movement therewith. The trailing arm connection canalternatively comprise a torque tube mounted to a portion of thetrailing arms rearward of the pivot pin.

The frame rail opening is preferably L-shaped and slidably receives aportion of the frame rail.

The modular suspension can further comprise a spring adapted to operablyconnect the trailing arm to the vehicle frame for resisting the pivotalmovement of the trailing arm about the pivotal axis toward the frame. Apair of shock absorbers can also be mounted to the modular assembly.Each of the shock absorbers has one end pivotally mounted to one of thetrailing arms and the other end adapted to be mounted to one of theframe rails. A positioning bracket can extend between the other end ofthe shock absorber and the air spring to fix the position of the otherend of the shock absorber in a position for mounting to the frame railwhen the modular suspension is slidably mounted on the frame rails. Atorsion torque rod extends from the axle to the cross beam and a lateralbrace extends from the axle to one of the rails.

In another embodiment, the invention relates to a method for installinga modular suspension on a vehicle frame having a pair of spaced C-shapedframe rails. The modular suspension comprises a pair of trailing armassemblies, each of which comprises a frame bracket and a trailing armhaving one portion pivotally mounted to the frame bracket for pivotalmovement about a pivot axis. A trailing arm connection extends betweenand is coupled to a portion of the trailing arms rearward of the pivotaxis. A cross beam extends between and is connected to the framebrackets with a rail opening therebetween for slidably receiving atleast a portion of one of the frame rails. The method comprises:aligning the frame rails with the rail openings, moving the modularsuspension longitudinally relative to the frame rails to insert therails into the rail openings, and affixing the cross beam and each ofthe frame brackets to the rails.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a modular trailing arm assemblyaccording to the invention;

FIG. 2 is a partial rear view of the modular trailing arm suspension ofFIG. 1; and

FIG. 3 is a partial front view of the trailing arm suspension of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a modular trailing arm suspension 10 according to theinvention mounted to a pair of vehicle frame rails 12. The modulartrailing arm suspension 10 comprises a pair of trailing arm assemblies14, each of which is mounted to a corresponding frame rail 12. Thetrailing arm assemblies 14 are identical or mirror images and only onewill be described in detail.

The trailing arm assembly 14 comprises a trailing arm 16 having a firstend and a second end. The first end is pivotally mounted to a hangerbracket 18 by a bushed connection 20 such as an elastomeric bushing. Thesecond end supports an air spring assembly 22, comprising a piston 24fixedly mounted to the trailing arm second end and a flexible member 26having a mounting plate 28 adapted to be secured to the vehicle framerail 12.

An axle bracket 30 is pivotally mounted to the trailing arm 16 by abushed connection 32. The axle bracket 30 includes an axle seat 34.

The trailing arm assembly 14 can include other components, such as ashock absorber 36, which has one end mounted to the trailing arm by alower shock bracket 38 and whose upper end is adapted to be mounted tothe vehicle frame rail 12 by an upper shock bracket 40.

In addition to the pair of trailing arm assemblies 14, the modulartrailing arm suspension 10 comprises a drive axle assembly 42 comprisinga differential housing 44 with axle housings 46. The axle housings 46are received within the axle seat 34 so that the drive axle assembly 42is carried by the trailing arm assemblies 14. A torque bar 48 has oneend pivotally mounted to the differential housing 44.

The modular trailing arm suspension 10 also comprises a cross beam 50extending between the hanger brackets 18 of the trailing arm assemblies14 and a torsion tube 52 extending between the second ends of thetrailing arms 16. A lateral rod or track bar 49 can be positionedbetween the differential housing 44 and the frame rail 12. A torque rod48 extends from the axle differential housing 44 to the cross beam 50.

The aforementioned trailing arm suspension components are well known andcurrently used in trailing arm suspensions. The invention advantageouslypreassembles these components into a modular trailing arm suspensioncapable of being directly mounted to the frame rails 12 as a unitarywhole. Referring to FIGS. 2-3, to form the module, the cross beam 50 iscoupled to the hanger brackets 18 through a connector such as a fillerplate 54, which is bolted between the cross beam 50 and the hangerbrackets 18. The size and position of the filler plate 54 are selectedto create an L-shaped gap 56 between the cross beam 50 and the hangerbrackets 18. The L-shaped gap 56 conforms to a portion of the C-shapedcross-sectional shape of the vehicle frame rails 12 and permits thevehicle frame rails to be slidably inserted between the cross beam 50and the hanger bracket 18, without the need for removing the fillerplate 54. In this manner, the modular trailing arm suspension 10 can beslidably mounted onto the vehicle frame rails 12 by aligning the framerails 12 with the L-shaped gap 56 and moving the modular suspensionlongitudinally relative to the frame rails. Alternatively, the framerails can be moved relative to the modular suspension.

The cross beam forms one connection between the pair of trailing armassemblies. The module is completed by forming a second connectionbetween the trailing arm assemblies. The second connection can be formedby either the axle or the torque tube. The first and second connectionsbetween the trailing arm assemblies form a box-like module that is anindependent, stand-alone structure. The spacing of the cross beam 50with respect to the hanger brackets 18 pre-arranges the cross beam 50and hanger brackets 18 for slidable mounting onto the vehicle framerails 12. The combination of the axle 42 and the torsion tube 52connecting the trailing arm assemblies further enhance the unitarystructure.

Additionally, other components in the modular trailing arm suspension10, such as the shock absorber 36, can be pre-positioned for directmounting to the frame rail. A temporary bracket 60 (FIG. 1) may extendbetween the air spring mounting bracket 28 and the upper shock bracket40 to fix the position of the shock 36 in its mounted position. Othercomponents can also be prearranged on the modular trailing armsuspension 10.

To assemble the modular trailing arm suspension 10 to the vehicle framerails 12, the modular trailing arm suspension 10 is slidably mountedonto the ends of the vehicle frame rails by inserting the vehicle framerails 12 into the frame rail gaps 56 and sliding the modular trailingarm suspension 10 to the desired location where bolt openings in thevarious components align with corresponding bolt openings on the framerails. Mounting bolts 58 are passed through the aligned bolt openingsand partially secured. The filler plates 54 are removed and the mountingbolts are completely tightened. The suspension components, such as theshock absorber 36, are also bolted to the frame rail as is the airspring 22.

The benefit of the modular trailing arm suspension 10 is that thepre-mounting of the cross beam 50 to the trailing arm assemblies withthe filler plate 54 permits the trailing arm assemblies 14 to bepre-assembled along with the torsion tube 52 and axle 42 into a modulethat is self supporting and capable of being directly mounted to thevehicle frame rails 12. The filler plate establishes the properorientation between the cross beam 50 and the hanger brackets 18 topermit the insertion of the vehicle frame rails 12 therebetween,enabling the slidable mounting of the modular trailing arm assembly 10to the vehicle frame rails.

The modular trailing arm suspension 10 greatly simplifies and speeds upthe assembly of the trailing arm suspension to the vehicle frame rail.In previous trailing arm suspensions, it was necessary to build up thetrailing arm suspension on the vehicle frame rails because the crossbeam was mounted on an opposite side of the frame rails 12 than thehanger brackets, essentially prohibiting any easy pre-assembling of thecross beam and the hanger brackets. The invention greatly reduces thedifficulty of installing the trailing arm suspension and permits themanufacturer of the trailing arm suspension to pre-assemble the trailingarm suspension into a module where it is shipped to the vehiclemanufacturer for assembly as a module or subassembly in the overallvehicle assembly.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that theembodiments described are illustrative of the invention and not alimitation of the invention. Reasonable variation and modification arepossible within the scope of the foregoing disclosure without departingfrom the spirit of the invention.

What is claimed is:
 1. A modular suspension adapted to mount on avehicle frame having a pair of spaced C-shaped frame rails, comprising:a pair of trailing arm assemblies, each trailing arm assemblycomprising: a frame bracket adapted to be mounted to one of the framerails; and a trailing arm pivotally mounted at one end to the framebracket for pivotal movement about a pivot axis; a trailing armconnection extending between and coupled to the trailing arms rearwardlyof the pivot axes; and a cross beam extending between the frame bracketsand connected to the frame brackets with openings therebetween shapedwith a profile of a size sufficient for slidably receiving at least aportion of the frame rails; whereby the modular suspension is mounted tothe associated frame rails by sliding the frame rails into and along theopenings between the cross beam and the frame brackets.
 2. The modularsuspension according to claim 1, and further comprising a connectormounted each of the frame brackets to the cross beam.
 3. The modularsuspension according to claim 2 wherein the connector comprises a spacermounted between a portion of each of the frame brackets and the crossbeam.
 4. The modular suspension according to claim 1 wherein thetrailing arm connection comprises an axle mounted to the trailing armsfor movement therewith.
 5. The modular suspension according to claim 4and further comprising an axle bracket resiliently mounted to each ofthe trailing arms and wherein the axle is mounted to the axle brackets.6. The modular suspension according to claim 4, and further comprising atorque rod mounted at one end to the axle and mounted at the other endto the cross beam.
 7. The modular suspension according to claim 4, andfurther comprising a lateral brace mounted to the axle at one end andadapted to be mounted to one of the frame rails at another end.
 8. Themodular suspension according to claim 1 wherein the trailing armconnection comprises a torque tube mounted to the trailing armsrearwardly of the pivot axes.
 9. The modular suspension according toclaim 1 wherein the openings between the cross beam and the framebrackets are L-shaped and slidably receive a portion of the frame rails.10. The modular suspension according to claim 1 wherein each trailingarm assembly further comprises a spring mounted to the trailing arm atone end and adapted to be operably connected to the vehicle frame atanother end for resisting the pivotal movement of the trailing arm aboutthe pivot axis toward the frame.
 11. The modular suspension according toclaim 1 wherein each trailing arm assembly comprises a shock absorberhaving one end pivotally mounted to the trailing arm and the other endadapted to be mounted to one of the frame rails.
 12. The modularsuspension according to claim 11, wherein each trailing arm assemblyfurther comprises a spring mounted to the trailing arm at one end andadapted to be operably connected to the vehicle frame at another end forresisting the pivotal movement of the trailing arm about the pivot axistoward the frame and further comprises a positioning bracket extendingbetween the other end of the shock absorber and the spring to fix theposition of the other end of the shock absorber in a position formounting to one of the frame rails when the modular suspension isslidably mounted on the frame rails.
 13. A method for installing amodular suspension on a vehicle frame having a pair of spaced C-shapedframe rails, the modular suspension comprising a pair of trailing armassemblies, with each trailing arm assembly comprising a frame bracketand a trailing arm having one portion pivotally mounted to the framebracket for pivotal movement about a pivot axis; a trailing armconnection extending between and coupled to a portion of the trailingarms rearward of the pivot axes; and a cross beam extending between andconnected to the frame brackets with a rail opening between each of theframe brackets and the cross beam shaped for slidably receiving at leasta portion of one of the frame rails; the method comprising: aligningeach of the frame rails with a corresponding one of the rail openings;moving the modular suspension longitudinally relative to the frame railsto insert the frame rails into and along the rail openings; and affixingthe cross beam and each of the frame brackets to the rails.